spi: spidev: fix lock inversion between spi_lock and buf_lock

{
  "id": "7f4e7cc970913bba3a7e713a84d51a8314ed5c78964c63cca5f0fece1bc9f704",
  "url": "https://osv.dev/vulnerability/CVE-2026-43319",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "spi: spidev: fix lock inversion between spi_lock and buf_lock",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: spi: spidev: fix lock inversion between spi_lock and buf_lock The spidev driver previously used two mutexes, spi_lock and buf_lock, but acquired them in different orders depending on the code path: write()/read(): buf_lock -> spi_lock ioctl(): spi_lock -> buf_lock This AB-BA locking pattern triggers lockdep warnings and can cause real deadlocks: WARNING: possible circular locking dependency detected spidev_ioctl() -> mutex_lock(&spidev->buf_lock) spidev_sync_write() -> mutex_lock(&spidev->spi_lock) *** DEADLOCK *** The issue is reproducible with a simple userspace program that performs write() and SPI_IOC_WR_MAX_SPEED_HZ ioctl() calls from separate threads on the same spidev file descriptor. Fix this by simplifying the locking model and removing the lock inversion entirely. spidev_sync() no longer performs any locking, and all callers serialize access using spi_lock. buf_lock is removed since its functionality is fully covered by spi_lock, eliminating the possibility of lock ordering issues. This removes the lock inversion and prevents deadlocks without changing userspace ABI or behaviour.",
    "evidence": "osv:CVE-2026-43319",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.142",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.75",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.16",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-43319",
      "aliases": [
        "CVE-2026-43319"
      ],
      "affected": [
        {
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "fabfed1afe273717ea33b8aee46b767360edbb80"
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                  "fixed": "f8431b8672231d378b03176fe74c95adfd3522cf"
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                {
                  "fixed": "e341e18215030af2136836b78508e0d798916df7"
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                {
                  "fixed": "41ccfac7d302968a4f32b5f7b012d066c5f5cdf8"
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                {
                  "fixed": "40534d19ed2afb880ecf202dab26a8e7a5808d16"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43319.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.2.0"
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                  "introduced": "6.13.0"
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                {
                  "fixed": "6.18.16"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.19.0"
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                  "fixed": "6.19.6"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43319.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.468917643Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/40534d19ed2afb880ecf202dab26a8e7a5808d16",
        "https://git.kernel.org/stable/c/41ccfac7d302968a4f32b5f7b012d066c5f5cdf8",
        "https://git.kernel.org/stable/c/e341e18215030af2136836b78508e0d798916df7",
        "https://git.kernel.org/stable/c/f8431b8672231d378b03176fe74c95adfd3522cf",
        "https://git.kernel.org/stable/c/fabfed1afe273717ea33b8aee46b767360edbb80",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43319.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43319",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43319.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43319",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492691,
  "published_at": "2026-05-08T13:26:14.231+00:00"
}